Big Idea:
Being able to understand and explain numbers will help students make sense of multi-digit computation and problem solving.

For this lesson, I wanted to use real-life data to provide students with a meaningful opportunity to round numbers. I knew that this would also support Math Practice 4: Model with Mathematics. Also, all of my students have recently been provided with Google email accounts so I have been experimenting with integrating Google Documents into lessons.

World Population Growth

Today, I began by emailing students a link to an article about the world population reaching 7 billion in October 2011. As students read the article, I asked them to share out surprising facts. After discussing the article, as well as questions and concerns, I showed students the following video:

Current Population Count

Then, I showed the current population count in the World and United States using this site. By this time, students were engaged and extremely interested in the concept of population growth.

Once all students were successful at copying the presentation and making it their own, we all discussed the first slide together, which was the Goal of the lesson. This was also the page that students took ownership of their presentation by adding, "By: First & Last Name." This is important as student ownership always translates into higher motivation and learning.

Connecting the World Population Growth to State Population Growth

Next, we moved on to the next couple of slides. I began with a Broad Question, asking students: About how many people live in each state? Students predicted which states were the most and least populated and shared their reasoning. Then, I wanted to present students with a more Narrow Question: About how much has each state's population grown over the past 10 years?

Estimating State Population Growth

We began by discussing the Estimated Population Growth in Wyoming (the least populated state in the U.S.). I included maps of each state so that students would also become more familiar with the geographic location of states alongside of rounding numbers. To estimate the population growth in Wyoming, I showed students how to round Wyoming's population in 2000 and 2010. Then, we subtracted to find the ten-year difference. I modeled this process again with Vermont. Only this time, students completed the population estimation chart while I Modeled Calculations.

Guided Practice

At this point, I asked team leaders (one student per group) to pass out white boards and markers to each student. I asked students to always check their estimated population growth calculations on their white boards: Showing Calculations.

To make sure students understood the process, we discussed and calculated the population growths for North Dakota and Alaska as well. For each state, I asked students to show their thinking on their white boards. During this time, I slowly released more and more responsibility to students and continually walked about the room, checking for understanding. Almost surprisingly, students caught on right away and were ready to practice with a peer.

Math partners are always easy to assign as I purposefully arrange student desks based on behavior, abilities, and communication skills. Also, when working with computers especially, it is always helpful if partners are sitting next to each other for quick and easy collaboration.

Expectations

To make sure all students were successful, I explained that I wanted to check their calculations on each slide before they moved on to the next state. I also reminded students that I was also looking for them to show their calculations on their white boards. After a while, students began Checking Calculations with a White Board and Calculator on the computer.

I loved the countless opportunities to discuss concepts outside of rounding. They were true teachable moments! Here, I discuss Negative Numbers with a student. At another point, I fell upon the opportunity to teach students the Parts of a Million so that students could say, "The population in this state grew 1/4 a million!"

Once I was able to observe my students working on this project, I could see how successful they were and how motivated they were to estimate the population growth in ALL states. When today's lesson came to an end, I knew that we just had to continue working on this lesson tomorrow!